An impeachment process against President Dilma Rousseff risks shaking the pillars of Brazil's democracy, Eduardo Cunha, the speaker of the lower house of Congress and one of Rousseff's main antagonists, said in an opinion article published on Friday by newspaper Folha de S. Paulo.

"I will never accept attempts to point me as the conspirator behind the impeachment of President Dilma Rousseff," Cunha wrote in the op-ed. "I have been reiterating that impeachments are not a resource for election losers, but a serious juridical tool to be used in very specific situations."

Cunha, who broke ranks with Rousseff's government in late July, also rebuffed accusations that he has been leading a campaign in Congress to undermine Rousseff's austerity policy by approving increases in public servant wages and watering down bills to cut government spending.

"There is no such thing as a 'Cunha's House.' The Chamber of Deputies is independent and driven by the majority of their representatives through their votes."

Opposition leaders have called for early elections or Rousseff's impeachment after she lost control of her political base in Congress and saw her popularity plummet to record lows.

Cunha, as House speaker, is responsible for opening impeachment proceedings. His PMDB party remains in Rousseff's coalition and also controls the Vice-Presidency and the Senate.

Cunha is being investigated for allegedly taking bribes in a corruption scandal at state-run oil firm Petrobras.